The present invention relates to dry shaving apparatus including a shaving head frame detachably fixed to the basic apparatus by at least one resilient latch element and carrying an apertured shear foil and a slidable shutter, which serves to optionally cover or expose the apertured shear foil and which, when it is displaced in the direction away from the apertured shear foil, can be displaced into a switching-on position latched by a latch, in which the apertured shear foil is exposed for shaving and the motor current circuit for the drive of the dry shaving apparatus is closed, which shutter, when it is further displaced in the direction away from the apertured shear foil, can be displaced from the switching-on position to a further position, in which the apertured shear foil and the shaving head frame are exposed by the shutter and the motor current circuit for the drive of the dry shaving apparatus is interrupted.
Such dry shaving apparatus is described in European Patent document EP-OS 0 290 073, in the embodiment of FIGS. 7, 8 and 9. In this known dry shaving apparatus, the further position for the slidable shutter is latched, like the switching-on position, by a latch. In this further position of the shutter, in which the dry shaving apparatus is not ready for use due to the interrupted motor current circuit, but both the apertured shear foil and the shaving head frame are exposed by the shutter, the shaving head frame can be removed without hindrance by the shutter from the basic apparatus, for example, for cleaning purposes or for exchange of the apertured shear foil. Since the shaving head frame is detachably fixed usually by means of at least one resilient latch element to the basic apparatus, in the further position of the shutter the shaving head frame must therefore be disengaged from the latch element cooperating therewith, for example by depression of a pushbutton displacing the latch element, which therefore requires a specific operation.
An object of the present invention is to further improve or simplify the manipulation of a dry shaving apparatus of the foregoing described type.
According to the invention, it is ensured for this purpose that the latch element cooperating with the shaving head frame is connected to a slide, which is displaceable parallel to the direction of displacement of the shutter and which cooperates with a spring, which attempts to pass the slide and the latch element connected to it to the latched position in which the shaving head frame is held and that the shutter, when it is displaced from the switching-on position to the further position, after it has left the switching-on position and after the motor current circuit has been interrupted, can be positively coupled with the slide and the slide can be taken along against the action of the spring cooperating with it by the shutter, the latch element being moved out of the latched position holding the shaving head frame and the shaving head frame being disengaged. In this manner, it is achieved that, when the shutter is displaced to the further position, the latch element automatically disengages the shaving head frame, as a result of which a specific operation is no longer required to permit in this further position of the shutter of simply removing by hand the shaving head frame from the basic apparatus. When the dry shaving apparatus is constructed so that the lower blade, which is usually pressed resiliently against the apertured shear foil and can be driven, is arranged not at the shaving head frame, but, as is common practice, at the basic apparatus itself, the shaving head frame, which in such a case carries alone the apertured shear foil, after it has been exposed, is pushed away from the basic apparatus or lifted therefrom by the latch element under the resilient force acting upon the apertured shear foil from the lower blade, which makes it still simpler to remove it by hand. When the shutter leaves the further position in the direction towards the apertured shear foil, the spring cooperating with the slide ensures that the slide and the shutter, due to the fact that they are positively coupled with each other, are commonly displaced in the direction towards the apertured shear foil to a position, in which the latch element again has reached the latched position, the motor current circuit then being interrupted. This can take place independently of the fact whether the shaving head frame has been brought at this instant into a position at the basic apparatus in which it can be held by the latch element, or whether it is still in the position in which it is removed from the basic apparatus. In case the shaving head frame has already been brought again by hand into the position provided for it at the basic apparatus, the latch element immediately engages in the latch at the shaving head frame and holds it at the basic apparatus. Otherwise, when the shaving head frame is still in a position in which it is disengaged from the basic apparatus and the latch element has already reached again the latched position, the shaving head frame can then be simply snapped into the elastically resilient latch element to arrange it at the basic apparatus, as a result of which it is held at the basic apparatus. As is apparent, in this manner, altogether a very simple operation of the dry shaving apparatus is obtained.
It has proved to be constructively very simple when the slide is constituted by a blade spring. In this manner, due to the construction of the slide as a spring the resilience required for the latch element is immediately obtained.
In this connection, it has further proved to be advantageous when the blade spring has at its end facing the shaving head frame a rectangularly bent hook-shaped part, which constitutes the latch element. As a result, the construction is further simplified because the slide and the resilient latch element constitute a part made in one piece.
As in the known dry shaving apparatus mentioned in the opening paragraph, for example the further position of the shutter as well as its switching-on position can be fixed by a latch element. As a result, it is ensured that, when the shaving head frame is removed from the basic apparatus, the motor current circuit for the drive of the dry shaving apparatus cannot be unintentionally closed. With a view to a further improvement of the operability of the dry shaving apparatus, however, it can be found to be advantageous when the further position of the shutter is not fixed, the shutter being displaceable from the further position together with the slide under the action of the spring cooperating with the slide in the direction towards the apertured shear foil until the latched position of the latch element connected to the slide is attained and the motor current circuit for the drive of the dry shaving apparatus remaining interrupted upon a further displacement of the shutter towards the apertured shear foil by means of a change-over switch until the shutter after a displacement beyond the switching-on position is again displaced in the direction away from the apertured shear foil into the switching-on position. In this embodiment, the shutter is therefore brought into the further position and is held therein by hand, in which position the shaving head frame can then be simply removed from the basic apparatus because it is held no longer by the latch element, after which the shutter must be released in order to return together with the slide and the latch element into a position in which the latch element is again in the latched position. As soon as the latch element has reached the latched position, again there is a possibility to arrange the shaving head frame at the basic apparatus in that it is snapped into the elastically resilient latch element and is thus held at the basic apparatus. In order that, also when in the present case the shaving head frame is removed from the basic apparatus, the motor current circuit for the drive of the dry shaving apparatus is prevented from being unintentionally switched on, it is further ensured that by means of the change-over switch the motor current circuit for the drive of the dry shaving apparatus remains interrupted until the shutter after a further displacement in the direction towards the apertured shear foil and beyond the switching-on position is displaced again in the direction away from the apertured shear foil into the switching-on position. It has been found that such an operation of the dry shaving apparatus can be carried out in a simple manner, it being ensured that, when the shaving head frame is removed from the basic apparatus, the motor current circuit for the drive of the dry shaving apparatus remains interrupted until the shutter is intentionally displaced in the direction away from the apertured shear foil into the switching-on position.
In this respect, it has further proved to be advantageous when there is provided between the switching-on position fixed by a latch and the unfixed further position of the shutter an additional position for the shutter which is fixed by a further latch and in which the apertured shear foil and the shaving head frame are exposed by the shutter and the motor current circuit for the drive of the dry shaving apparatus is interrupted, while the further latch is constituted on the one hand, viewed in the direction of displacement of the shutter away from the apertured shear foil, by the slide acted upon by the spring when the latch element is in the latched position and on the other hand, viewed in the direction of displacement of the shutter towards the apertured shear foil, by at least one fixed abutment. When for the shutter such an additional position is provided, which is fixed by a further specifically constructed latch, a defined position of the shutter is obtained, in which the motor current circuit for the drive of the dry shaving apparatus is interrupted and, when the latch element is in the latched position, the shutter is situated immediately before the position in which it is operatively positively coupled with the slide or immediately behind the position in which the shutter is operatively decoupled from the slide, depending upon the direction of displacement in which the shutter reaches this additional position, i.e. either from the switching-on position or from the further position. As a result, on the one hand a fixed starting point is obtained to be able to remove during a further process the shaving head frame from the basic apparatus, which is made possible by displacing the shutter into the further position, while on the other hand the shutter and the slide return, after they have left the further position, to a defined position corresponding to the aforementioned starting point, in which the latch element is in the latched position so that the shaving head frame can be arranged in a precise manner at the basic apparatus.
It has further proved to be advantageous when between the outer side of the shaving head frame and the basic apparatus at least one straight line guiding is provided, which defines the direction of the movement of removal of the shaving head frame from the basic apparatus. Thus, both the removal of the shaving head frame from the basic apparatus and the placement of the shaving head frame on the basic apparatus are effected in a very precise and reliable manner.
It has also proved to be advantageous in a dry shaving apparatus, in which the apertured shear foil cooperates with a lower blade, which is arranged at the basic apparatus and is resiliently pressed against the apertured shear foil, when between the shaving head frame and the basic apparatus elastically resilient abutment stops are provided, which cooperate with each other in the direction of the movement of removal of the shaving head frame from the basic apparatus and which limit the movement of lifting the shaving head frame from the basic apparatus after disengagement of the shaving head frame by the latch element under the action of the spring-loaded lower blade. In this manner, when the shaving head frame is disengaged by the latch element, the shaving head frame cannot unintentionally fall downwards from the basic apparatus, which could occur under the resilient force acting from the lower blade upon the apertured shear foil. Due to the elastically resilient construction of the abutment stops, the shaving head frame can then be removed without great effort by hand, while overcoming the abutment stops, from the basic apparatus in a simple and reliable manner.
In a dry shaving apparatus, in which both a straight line guiding as mentioned above is provided and the aforementioned abutment stops are used, it has further proved to be advantageous when the abutment stops are provided at the area of the straight line guiding. In this manner, a very simple and space-saving construction is obtained.